This invention relates to drying microsurfaces, such as semiconductor wafers, during manufacture.
During the manufacture of semiconductor wafers, it is common that liquid chemical processing take place at various steps in the manufacturing process. Commonly, these xe2x80x9cwet chemicalxe2x80x9d steps will involve relatively harsh chemicals such as hydrofluoric, sulfuric, phosphoric, and nitric acids and ammonium hydroxide, and the like. These harsh wet chemicals are used for a variety of steps such as film removal, cleaning, and surface conditioning.
Harsh wet chemicals used in a particular processing step must be removed from the wafer prior to subsequent processing. Currently, the industry commonly uses a simple water rinse with deionized (e.g., distilled) water. Unfortunately, deionized water actually dissolves minute quantities of silicon from the surface of the wafer. When evaporated off the wafer, the deionized water will typically leave small deposits of dissolved silicon in various surface structures on the wafer. These deposits, known as xe2x80x9cwatermarksxe2x80x9d are usually harmless, but will occasionally deposit in a critical location and render the wafer inoperative. Hence, a certain percentage of defects during manufacture are attributable to such watermarks and could be eliminated if a way were found to remove deionized water without evaporation.
Disclosed herein is a method of drying water from surface without evaporation by utilizing capillary action. The invention is particularly useful for microsurfaces, meaning surfaces that have microscopic detail and features, particularly the surfaces of semiconductor wafers. A plurality of capillary channels are bundled to form a drying plate that is then brought in contact with the wet wafer surface, thereby drawing off the water. In a preferred embodiment, a flow of gas is provided across the upper openings of the capillary channels in order to enhance the capillary action. The invention may be generalized to liquids other than water.